Hey guys! I was wondering if anyone could help me figure out how the artist 
Timothy Reynolds (Check out his work, it's great), achieves his work.

I'm hoping it was generated, because I want to make a large-scale terrain and I really don't want to have to do it all by hand. Is there any way you can generate terrain with a similar style to this? If anyone can help on this, I'd really appreciate it.
 
                    
                 
            
Replies
Gives you a starting point, then go polishing until it's good!